| 摘要 |
PCT No. PCT/CH86/00157 Sec. 371 Date Jul. 16, 1987 Sec. 102(e) Date Jul. 16, 1987 PCT Filed Nov. 13, 1986 PCT Pub. No. WO87/03287 PCT Pub. Date Jun. 4, 1987.The invention is concerned with a novel process for the manufacture of compounds of the formula <IMAGE> I wherein R1 signifies C1-5-alkyl, especially methyl, ethyl, propyl or isopropyl, and the radicals R2 each independently represent hydrogen or C1-5-alkyl, especially hydrogen or methyl, ethyl, propyl or isopropyl. The process is characterized in that a compound of the formula <IMAGE> II wherein R stands for C1-4-alkoxy, chlorine, bromine or C1-4-alkanoyloxy, R1 and R2 have the above significance and R3 represents C1-4-alkyl. is hydrolyzed and subjected to an aldol condensation and, where R=C1-4-alkoxy, the reaction product is subsequently subjected to an acid treatment. The compounds I are for the most part known flavoring substances. |
